1. Field of the Invention
The present invention relates to an angular velocity sensor device used in an attitude control apparatus and in a navigation system for mobiles such as airplanes, cars, and other vehicles.
2. Description of the Related Art
One example of a conventional angular velocity sensor device is disclosed in Japanese Laid-Open Patent Publication No. 4-236321. The angular velocity sensor device includes an angular velocity sensor, a circuit board having a circuit for driving the angular velocity sensor and processing a signal output from the angular velocity sensor, a holding plate for holding both the angular velocity sensor at the longitudinal ends thereof via shock absorbers and the circuit board, and a case for accommodating the angular velocity sensor, the circuit board, and the holding plate as one unit.
The conventional angular velocity sensor device having the above structure will be described with reference to FIGS. 8 to 10.
FIG. 8 is an exploded perspective view of a conventional angular velocity sensor device 15 where a case 11 is removed from a body 12. FIG. 9 is a side view of the body 12. FIG. 10 is a perspective view of a base 8 of the body 12, which is the main portion of the conventional angular velocity sensor device 15.
Referring to FIGS. 8 and 9, an angular velocity sensor 1 is secured to a holder 2. A sub circuit board 4 is mounted around and connected to an output terminal 3 of the angular velocity sensor 1. The sub circuit board 4 is connected via a lead 5 to a main circuit board 6 mounted on the base 8, thereby realizing the connection of the angular velocity sensor 1 with a circuit pattern (not shown) formed on the main circuit board 6.
Three leads 7a, 7b, and 7c are connected to the main circuit board 6 for inputting/outputting signals and grounding, respectively. In FIG. 9, these leads 7a, 7b, and 7c are collectively denoted as a lead 7 for simplification.
The base 8 shown in more detail in FIG. 10 also works as a holder for the angular velocity sensor 1. For this purpose, the base 8 includes a pair of sensor holding portions 8a which have respective recesses 8b opposing each other. First and second shock absorbers 9 and 10 are pressed into and attached to the respective recesses 8b at one end. The other end of the first shock absorber 9 is pressed into and attached to the holder 2 of the angular velocity sensor 1. The other end of the second shock absorber 10 is connected with the output terminal 3 of the angular velocity sensor 1.
The body 12 is mainly composed of the angular velocity sensor 1, the main circuit board 6, and the base 8 and is accommodated in the case 11, so as to complete the angular velocity sensor device 15. As is apparent from the above description, the angular velocity sensor 1 of the conventional angular velocity sensor device 15 is held at the longitudinal ends by the sensor holding portions 8a of the base 8 via the shock absorbers 9 and 10.